51576721 has 4 divisors (see below), whose sum is σ = 58944832. Its totient is φ = 44208612.

The previous prime is 51576713. The next prime is 51576727. The reversal of 51576721 is 12767515.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12767515 = 5 ⋅2553503.

It is not a de Polignac number, because 51576721 - 2³ = 51576713 is a prime.

It is a super-2 number, since 2×51576721² = 5320316298223682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51576727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3684045 + ... + 3684058.

It is an arithmetic number, because the mean of its divisors is an integer number (14736208).

Almost surely, 2^51576721 is an apocalyptic number.

It is an amenable number.

51576721 is a deficient number, since it is larger than the sum of its proper divisors (7368111).

51576721 is an equidigital number, since it uses as much as digits as its factorization.

51576721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7368110.

The product of its digits is 14700, while the sum is 34.

The square root of 51576721 is about 7181.6934632439. The cubic root of 51576721 is about 372.2356029578.

The spelling of 51576721 in words is "fifty-one million, five hundred seventy-six thousand, seven hundred twenty-one".